Examples of constituent elements of circuits for increasing or decreasing a voltage include reactors. For example, JP 2017-28142A discloses a reactor including: a coil having winding portions, a magnetic core arranged inside and outside the coil (winding portions) to form a closed magnetic circuit; and an insulating interposed member interposed between the coil (winding portions) and the magnetic core. The magnetic core includes inner core portions arranged inside the winding portions, and outer core portions arranged outside the winding portions. The insulating interposed member includes inner interposed members interposed between inner peripheral faces of the winding portions and the inner core portions, and end face interposed members interposed between end faces of the winding portions and the outer core portions. The reactor described in JP 2017-28142A further includes inner resin portions that fill gaps between the inner peripheral faces of the winding portions of the coil and the inner core portions, and outer resin portions that coat parts of the outer core portions.
In the reactor described in JP 2017-28142A, inner interposed members are interposed in parts of gaps between the winding portions and the inner core portions, and thus gaps (resin flow paths) are formed in the remaining portion between the inner peripheral faces of the winding portions and the outer peripheral faces of the inner core portions. Then, resin is caused to coat the outer perimeters of the outer core portions, and to flow into resin filling holes formed in the end face interposed members, so that the resin flow paths are filled with the resin from the end face sides of the winding portions, thereby integrally molding the outer resin portions and the inner resin portions.
JP 2017-28142A is an example of a related art.